Electron tube for very high frequencies



Nbv'. IL-"1952 BRUCK 2,617,961"

ELECTRON TUBE FOR VERY} HIGH FREQUENCIES Filed Dec 27 1947 E g E 2 Sl-lEETS- SI-EET 1 nv vt-W rag .4 07/01 R zsvwc/r Z 1 d d; (i 44 kifTOR/V') Nov. 11, 1952 L. BRUCK 2,617,961

ELECTRON TUBE FOR VERY HIGH FREQUENCIES Filed Dec. 27, 1947 2 sxmE'rs-srmm 2 w P F l/VVE/VO? [Of/7AA BRuc/r,

'' Af7'0 IVEY For securing a selective amplification, the space surrounding the cathode must be, according to the invention, divided up into sectors consistent with a suitable grouping of the electrons for a given frequency. Only the sectors having suitable phase relations will be travelled through by the electrons; and in the other sectors there Will be no electrons. That division into sectors can be determined by means of bars or rods B (Fig. 4) carried to a negative potential with regard to the cathode K and placed before or behind the positive grid G. The bars B are parallel with the cathode K. Fig. 4 is a view similar to Fig. 3, with parts designated by the same reference letters, showing a tube according to the invention equipped with these bars 13. When wishing to change the frequency intended to be amplified, it is sufficient to simply displace the bars on the circle on which they are disposed. I In the elevational portion of Fig. 1 there is shown by way of illustration a system N1, N2 formed of two solenoids in opposition, capable of establishing the radial magnetic field heretofore described. I have designated the connection to the inner end A of the spiral through a coaxial cable B1, C1 similar to the coaxial cable R2, C2 where the outer conductor R1 connects with the envelope M and the inner end conductor C1 connects to the inner terminal of the spiral S2.

Another process for changing the frequency to be amplified consists in displacing the sectors containing the electrons by carrying the bars B to different potentials. Indeed by changing these potentials it is possible to displace the sectors of grouping so as to obtain a frequency variation.

For obtaining a low electron speed, it is possible to concentrate the electric fields in the slits F of the guide (Fig. For this purpose the slits are made narrower by means of spiral plates applied against the cut-out edges along L in the guide Figs. 3 and 5). Under these conditions, the transit time in each one of the slits becomes small enough to permit the transfer of energy from the electrons to the wave in each one of the slits considered alone. In order that the energy transfer be effected in all the slits, it is moreover necessary to adjust the transit time in the spaces of the guide free of any field. This is accomplished by controlling the D. C. voltage applied to the guide, so that the electrons meet with the same phase relations when passing successively in front of all the slits.

Fig. 5 shows a perspective view of a non-limiting example of a form of tube having such slits F. The figure shows the tube in perspective out by a median plane. In the center of the tube at K, is the emissive cylindrical cathode, surrounded by the grid G formed of metallic bars likewise distributed on a cylinder co-axial to said cathode. At W I have shown the focalizing wehnelt of the electronic beam. The walls of the rectangular guide are split and wound in spirals as shown at P. A and E designate respectively rectangular guides serving as energy inlet and evacuation channels.

Lastly, by introducing reactive coupling means in their connections, the above described tubes can be used as oscillators.

What I claim is:

l. A traveling wave tube comprising a retardaspirals, means comprising an ultra-high frequency conduit coupled with said input for injecting therein ultra-high frequency waves for the two spirals situated near their center, means for injecting into the space between these spirals an electron beam emanating from the center of the spirals and directed along their radii, and means for giving to the beam of electrons a velocity substantially equal to the apparent velocity of phase propagation of the wave in the radial direction.

2. A traveling wave tube as set forth in claim 1, wherein the conductor of the spirals has a hollow cross section adapted to guide the ultra-high frequency wave.

3. A traveling wave tube as set forth in claim 1, wherein the means for injecting the beam comprise a cathode situated in the center of the spirals and surrounded by a grid connected to source of positive potential relative to the cathode.

4. A traveling wave tube as set forthin claim 1 in combination with means for applying a constant magnetic field whose lines of force follow the direction of the radii of the spirals.

5. A traveling Wave tube as set forth in claim 1, wherein the conductor of the spirals has a hollow cross section adapted to guide the ultra-high frequency wave, the interior of the guide being separated from the circulation space of the beam by a partition having a spiral-shaped slot.

6. A traveling wave tube as set forth in claim 1, with means for cutting up the electronic emission into a plurality of radial beams.

7. A traveling wave tube as set forth in claiml, wherein the emitting system of the beam comprises a cathode surroundedby a network of bars connected to sources of negative potentialrelative to the cathode and serving to cut up the electronic emission into a plurality of radial beams.

8. A traveling wave tube, as set forth in claim 1, wherein the emitting system of thebeam comprises a cathode surrounded by a network of bars connected to sources of negative potential relative to the cathode and serving to cut up the electronic emission into a plurality of radial beams, and means for making the potentials of these bars vary.

9. A traveling wave tube as set forth in claim 1, wherein the emitting system of the beam comprises a cathode surrounded by a network of bars connected to sources of negative potential with respect to the cathode and servingto cut up the electronic emission into a plurality of radial beams, said bars being equally spaced in a circular path.

LOTHAR BRiicKj REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,064,469 Haefi Dec. 15, 1936 2,298,949 Litton Oct. 13, 1942 2,300,052 Lindenblad Oct. 2'7, 1942 2,320,860 Fremlin June 1, 1943 2,367,295 Llewellyn Jan. 16, 1945 2,402,983 Brown July 2, 1946 2,420,342 Samuel May 13, 1947 2,457,524 Bowen Dec. 28, 1948 2,514,678 Southworth July 11, 1951 

